1. Field of the Invention
This invention relates to a process for the production of decahydroisoquinoline, and more particularly to a process for the production of decahydroisoquinoline by the hydrogenation of isoquinoline or partially hydrogenated isoquinoline.
2. Description of the Prior Art
Decahydroisoquinoline is destined to find growing utility as raw material for medicines and agricultural pesticides.
As means of producing decahyroisoquinoline by the hydrogenation of isoquinoline, the method using platinum oxide as a catalyst and the method using Raney nickel as a catalyst for the hydrogenation have been known to the art.
The method which uses platinum oxide as the hydrogenation catalyst is impracticable because the platinum oxide itself is too expensive to permit commercial production of decahydroisoquinoline and the method which uses Raney nickel as the hydrogenation catalyst entails a disadvantage that the hydrogenation readily produces 1,2,3,4-tetrahydroisoquinoline, produces decahydroisoquinoline with difficulty, and yields by-products in large amounts.
The inventors continued a diligent study directed to elucidation of the causes for the drawbacks experienced to date and development of a process capable of producing decahydroisoquinoline advantageously. We have consequently found that use of a ruthenium catalyst as a hydrogenation catalyst permits economic production of decahydroisoquinoline. This knowledge has led to perfection of the present invention.